Class 11 · Chapter 2
Physical World & Measurement
Overview, notes, short notes, formula sheet, daily practice problems, previous year questions, and videos for this chapter — all in one place.
Physical World & Measurement JEE Notes
These are fully worked, JEE-style problems on units, dimensions, and error analysis — the kind of multi-step reasoning JEE Main and JEE Advanced actually test, beyond the straightforward formula plug-ins in the regular DPP.
The time period T of a simple pendulum is believed to depend on its length l and the acceleration due to gravity g, as T = k·lᵃ·gᵇ for some dimensionless constant k. Use dimensional analysis to find a and b.
A new system of units takes force, length, and time as fundamental quantities, with 1 unit of force = 10 N, 1 unit of length = 2 m, and 1 unit of time = 4 s. Find the value (in kg) of 5 units of mass in this new system.
A quantity X is calculated as X = A²B³/C. If the percentage errors in measuring A, B, and C are 1%, 2%, and 3% respectively, find the percentage error in X.
A vernier caliper has a least count of 0.01 cm and a negative zero error of 0.02 cm. For a measurement, the main scale reads 3.4 cm and the 5th vernier division coincides with a main scale line. Find the corrected reading.
Evaluate (12.5 × 0.0028) / 3.2, reporting the answer to the correct number of significant figures.
Check whether the equation v² = u² + 2as (a standard kinematics equation) is dimensionally consistent.
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